A silicone having a hydrophilic group has superior surface activity power because of possessing both a silicone moiety exhibiting properties such as a hydrophobic property, flexibility, a lubricating property, chemical stability and the like, and a hydrophilic-group moiety exhibiting properties such as a hydrophilic property, a moisture-retaining property, an adhesive property and the like. For this reason, the silicones having hydrophilic groups are widely used in food, resins, paint, cosmetics and the like. In particular, in a cosmetic, a silicone oil such as a low-molecular cyclosiloxane or the like is blended in order to improve sensation during use in many cases. It has been proposed that as a cosmetic raw material such as a surfactant or the like, for example, a polyether-modified silicone is used due to good miscibility with a silicone oil in many cases (JP-A-S61-293903 and the like).
However, a polyether group is sometimes insufficient in view of a hydrophilic property. For this reason, a (poly) glycerol-modified silicone and the application thereof to a cosmetic have been proposed in order to improve the hydrophilic property (see JP-A-S57-149290, JP-A-H06-157236, JP-A-H09-071504 and JP-A-2005-042097). However, the hydrophilic property may be still insufficient even in the case of using the (poly)glycerol group. In order to further enhance hydroxyl-group density, a sugar-modified silicone using a sugar or a polysaccharide as a polyhydric alcohol, and the application thereof to a cosmetic have been proposed (see JP-A-S62-068820, JP-A-S63-139106, JP-A-H05-186596, JP-A-H07-041417, JP-A-2002-119840, JP-A-2008-274241 and JP-A-2002-179798).
On the other hand, an oil agent used in a cosmetic is not restricted to a silicone oil, and various types of oil agents such as a hydrocarbon oil, an ester oil and the like or a mixture thereof are used. For this reason, a material having surface activity power which is superior in miscibility with respect to various types of oil agents, an emulsifying property, stability of the emulsion and the like has been desired. The sugar alcohol-modified silicones described in JP-A-S62-068820, JP-A-S63-139106, JP-A-H05-186596, JP-A-H07-041417, JP-A-2002-119840, JP-A-2008-274241 and JP-A-2002-179798 have the characteristic of a sugar alcohol group which is rich in a hydrophilic property, but the surface-active effect thereof is still restrictive. A surfactant which can stably emulsify various types of oil agents containing not only a silicone oil, but also an organic oil has been desired.
In addition, the aforementioned sugar alcohol-modified silicone has problems described below.
JP-A-S62-068820 and JP-A-S63-139106 indicate a sugar alcohol-modified silicone in which a sugar alcohol residue is bound to a silicone via an amino group, and an application thereof to a cosmetic. However, the sugar alcohol-modified silicone obtained by the aforementioned method contains an amino group, and for this reason, the usages thereof are restricted. For example, for use in a cosmetic, the sugar alcohol-modified silicone is restrictly applied a hair cosmetic due to skin irritation.
JP-A-H05-186596 indicates examples of a sugar alcohol-modified silicone in which a sugar alcohol residue is bound to a silicone via an oxygen atom. However, JP-A-H05-186596 merely describes simple evaluation results of miscibility with an oil agent and an emulsifying property, and fails to describe a blending example in a cosmetic or the blending effects thereof. In addition, there is no description about the molecular structure therefor, and the evaluation results are also insufficient in view of effects of emulsifying various oil agents. In addition, JP-A-H05-186596 merely describes that the sugar alcohol-modified silicone may be applied to a cosmetic, and fails to describe detailed formulation effects.
JP-A-H07-041417 describes examples in which a sugar alcohol-modified silicone having a sugar alcohol residue bound to a silicone via an oxygen atom is applied to a hair cosmetic. However, JP-A-H07-041417 merely describes effects as a hair cosmetic, and fails to clarify the miscibility with oil agents and blending effects.
JP-A-2002-119840 describes an example in which a sugar alcohol-modified silicone having a sugar alcohol bound to a silicone via an intermediate binding chain is applied as a surfactant. However, JP-A-2002-119840 describes a method for producing the aforementioned sugar-modified silicone, but fails to sufficiently describe the structure of the organosilicon compound which is a silicone component or the detailed functions thereof. In addition, the evaluation for emulsifying ability thereof is extremely restricted.
In addition, in a sugar alcohol-modified silicone described in JP-A-2008-274241, the structure of the silicone component is specified, but evaluation results of emulsifying with a silicone oil are merely described, and there is no description regarding an emulsifying property or compatibility with other oil agents or no description regarding a blending example in a cosmetic or blending effects.
In addition, JP-A-2002-179798 describes a silicone modified with a polyhydric alcohol covering a sugar alcohol and the application thereof to a cosmetic. The aforementioned polyhydric alcohol-modified silicone contains branches derived from linear silicone chains in a molecule, and for this reason, miscibility with a silicone oil may be improved. Even if, miscibility with a silicone oil can be enhanced by introducing the linear silicone chains, it is difficult to enhance miscibility with widely-ranged organic oil agents such as a hydrocarbon oil, an ester oil and the like. Use of the aforementioned polyhydric alcohol-modified silicone as a surfactant is insufficient in view of emulsifying widely-ranged oil agents and stability of the emulsions. In addition, the obtained emulsions impart a strong oily feeling on touch, and therefore, are insufficient emulsions.
On the other hand, a sugar alcohol-modified silicone having a siloxane dendron structure is proposed (JP-A-2003-146991). Although the aforementioned sugar alcohol-modified silicone is superior in view of a hydrophilic property since the sugar alcohol group is present at the terminal of the molecule, it is difficult to sufficiently exhibit properties of the siloxane dendron structure since the sugar alcohol group binds to the siloxane dendron structure. Therefore, the aforementioned sugar alcohol-modified silicone is inferior in view of affinity and miscibility with various types of oil agents. In addition, JP-A-2003-146991 merely describes that the sugar alcohol-modified silicone can be applied to a cosmetic and fails to describe detailed formulation effects thereof.
As described above, in conventional sugar alcohol-modified silicones, insufficient miscibility with widely-ranged oil agents is exhibited. For this reason, a surfactant exhibiting a superior emulsifying property and superior stability of an emulsion has been desired. In addition, an emulsion obtained by the aforementioned surfactant, which has a wide application range and exhibits superior storage stability, has been desired.
As application examples of the silicones having hydrophilic groups, mention may be made of, in addition to a surfactant, a powder treatment agent for modifying conditions of the surface of inorganic powders or organic powders by effectively coating the surface thereof, a powder which has been subjected to a surface treatment with the aforementioned powder treatment agent, a mixture between a powder treatment agent and a powder, and a composition in which the silicones are dispersed in an oil agent such as a silicone oil, a hydrocarbon oil, an ester oil or the like. However, in the application of the polyhydric alcohol-modified silicone containing a sugar alcohol to a cosmetic, JP-A-2002-179798 describes an example of a cosmetic composition containing a powder, but fails to describe a dispersing property of the powder, and the effects thereof are insufficient. In addition, JP-A-2002-038013 describes an example of using a silicone having an alcoholic hydroxyl group in a powder treatment, but merely describes modification with a (poly)glycerol group, and fails to indicate effects due to a sugar alcohol group.